Purification of oil



y 1938. m. I. mum/um 3,116,344

'PuRIF'IoATIoN OF on,

Filed March 50, 1935 2 Sheets-Sheet 1 I INVENTOR m yawa R. P. ouwvum-z 2,116,344

PURIFICATION OF OIL Filed March so, 1955 2 Sheets-Sheet 2 INVENTOR Patented May 3, 1938 UNITED STATES 2,116,344 PURIFICATION F 01!.

Russell P. Dunmire, Alliance, Ohio, assignor, by mesne assignments, to The Buckeye Labo tories, Inc., Alliance, Ohio, a

Ohio

on of Application March 30, 1935, Serial No. 13,893

'1 Claims.

This invention relates to the purification of oil, and more particularly to a process oi reclaiming hydrocarbon oils, such as cable, transformer and switch oils. The process not only removes solids in colloidal suspension, but also dehydrates, de-' 'gasifies, demulsifles and decolorizes the oil, rendering it suitable for re-use.

In the accompanying drawings, which illustrate two embodiments of my invention,

0 Figure 1 is a general lay-out view showing the complete apparatus; and

Figure 2 is a similar view illustrating a slightly modified form of the invention.

Describing the preferred process generally, the

13 impure 6r dirty oil is passed through a primary filter to remove-solids and is then heated and introduced under pressure into a combined degasifler and mixer. The oil is atomized or sprayed in fine particle form into the degasifler which is m maintained under high vacuum, thereby causing the release of moisture and gases from the oil. The moisture and gases'are withdrawn from the vacuum chamber by a vacuum pump connected to the chamber. The degasifled oil is then collected and passed in film form over baifles within the chamber and is delivered to a mixing chamber which is in communication with the desasifler chamber and which also is maintained under a high vacuum. Duringthe time that the oil is being sprayed into the vacuum char, an adsorbent material is supplied to the oil. The adsorbent material is also maintained under vacuum 'while it is being supplied to the oil in a loose, finely divided state, thereby dehydrating it and u materially reducing the foam which would be produced otherwise if the adsorbent material was added directly to the oil without dehydrating it. when the adsorbent material is added to the oil, gases are liberated from the adsorbent material a and from; the oil. In the-present invention, the

vacuum is applied simultaneously with the introduction of the adsorbent material in loose, finely divided condition into the oil so that the gases are acted upon immediately upon. their liberation I and withdrawn from the vacuum chamber.

The degasifled oil and adsorbent material are then passed to a filter which removes the adsorbent material with its adsorbed impurities. This filter is preferably 01 the rotary cake type. The

50 oil is then passed to a blotter type filter which removes any solids which may still remain in the 011, after which the oil is passed to a secondary degasifier. The oil is sprayed or atomized into fine particlesin the secondary degasifier which is ll maintained under reduced pressure so as to liberate any gases or moisture which may still remain in the oiL The oil is then passed to a storage tank which is maintained under reduced pressure and regulated temperature until such time as it is desired to use it.

Referring more particularly to the accompanying drawings, and for the present to Figure 1, the impure or dirty oil is admitted through a pipe 2 provided with a valve 3. It flows through a primary filter 4 provided with a drain 5 and then through pipe 6 provided with a sight gauge 1 to a high pressure pump 8 driven-by a motor 9. The oil is then passed through a pipe Hi to a heater ll. The heater is heated by steam admitted through an inlet II, the heater being provided with a temperature regulator 13. The steam exits through a pipe H. The steam heats the oil by indirect means rather than direct contacttherewith, thetemperature of the oil being raised in the heater preferably to 140-275 F.

heated oil is then passed through a pipe IE to a degasifler and mixer indicated generally by the reference numeral l6.

The oil delivered through pipe I5 is preferably under a pressure oi 100 to 250 pounds per square inch and the vacuum maintained in the degasifler is preferably from 28.5 to substantially inches oi mercury as reierred to a 30 inch barometer.

The combined degasifier' and mixer consists of two sections ll and I8 which are, respectively, 30

the degasifying section and the mixer section.

The degfler section I! comprises ,a casing IS in which is provided a hood-shaped baffle 20. Below the bee 20 are other bailles 2| so arranged as to cause c all which falls down from the baiile 2% onto the baiiies 2| to follow a tortuous path to the bottom of the degasifier section. Also located inside of the casing are spray nozzles 22 connected together by a pipe 23 and also connected to the pipe it. Mounted on the top 0! the section ii are two hoppers 24 and 26. These hoppers are provided, respectively, with feeding devices 25 and 21, which are operated bymotors 28 and it. Adsorbent material contained'in the hopper it is fed by the feeding device 26 through 4,5

an extension ti of the hopper into a tube, 32. This tube is open 'at the bottom so that the adsorbent material is fed into the oil which collects in the mixing section ii. The adsorbent material is preferably a'mixture of fullers earth, activated carbon anda silicious material to act as a filter aid, preferably that sold under the trade name Hyflo Super-Gel" in-the proportions preterably oi! one-half to one and one-half percent of a mixture oi. iuilers earth and activated carbon and from one-tenth to one-half percent of the silicious material.

The feeding device 21 feeds a precoating material contained in the hopper 25 through an extension 33 into and through a tube 35 to the oil in the mixer section I8. It will be understood that the precoating materialis for the purpose of forming a filtering surface on the filters which are referred to hereinafter, and that after the filtering surfaces havebeen prepared, the precoating material is no longer fed to the oil in the section I0 from hopper 25.

The oil which is fed to the degasifier section II under high pressure is atomized or sprayed by the nozzles 22 so as to break it up into very fine particles. Since the degasifier section is maintained under high vacuum, the particlesof oil are subjected to a sudden pressure drop or shock which releases moisture and gases from the oil particles. The moisture and gases so released are withdrawn from the degasifier through pipe 40 provided with valve H and pipe 42 which is connected to a vacuum pump 43.

The oil which has flawed in film form over the baffies 2| while exposed to the vacuum then flows through an opening 45 into the mixer section I8 and the adsorbent material discharged from the lower end of the tube 32 is here mixed with the degasified oil. The oil and adsorbent material are agitated by a rotatable stirrer consisting of paddles 46 mounted on a vertical shaft 41. Adjacent to the paddles 46 are stationary bailies 48 which aid in the thorough mixing of the adsorbent material and oil. The shaft 41 extends upwardly through the opening 45 and through the degasifier section I1 and is connected at its upper end to a motor 49 by means of which it is rotated. The mixture section I8 is heated by means of steam pipes 50 within the casing 5| of the mixer. Steam is admitted to the pipes 50 through a pipe 52 and exits therefrom through a pipe 53. A temperature regulator 54 is provided for maintaining the proper temperature in the mixer. It is preferred to maintain the mixture of oil and adsorbent material at a temperature between 250 F. and 600 F. This high temperature treatment without deterioration of the oil is possible due to the previous spraying or 'atomizing of the oil into the degasifier section I! which removes the greater part of the impurities. Heating the oil at this stage of the process permits the rapid removal of any gases or moisture remaining in the oil, which gases or moisture may have been present in the impure oil or which may have been introduced into the oil due to the addition of the adsorbent material. It will be noted, however, that the adsorbent material is in a loose, finely divided state and under vacuum during its passage from the hopper 24 to the oil in the mixer section I 0, and thus the greater portion of any moisture or gases originally present in the adsorbent material are removed before the adsorbent material contacts with the oil. This materially reduces the tendency of the mixture of oil and adsorbent material to foam.

The oil fiows out of the mixer section I0 through a pipe 60 controlled by a. valve SI and is pumped by a pump 82 connected to a motor 63 through pipe 64 and pipe 65 provided with a valve 66 to a filter 61 which preferably is of the rotary cake type. The filter removes the adsorbent material and the clear oil then passes through a pipe 68 to a surge tank 69 and from the surge tank through a pipe I0 to a pump II connected to a motor 12, which pump delivers the oil through pipe I3 provided with a valve I4 to a secondary filter I5. The secondary filter is provided so that in the event that the cake in the rotary cake filter breaks, the secondary filter will be effective for removing any solid material passing through the rotary filter.

The oil is passed from the filter i5 through pipe I6 provided with a valve 11 and pipes I8 and I9 to a secondary degasifier indicated generally by the reference numeral 80. The pipe I9 delivers the oil under pressure, preferably from 10 to 50 pounds per square inch, to spray or atomizing nozzles 8| located within the secondary degasifier 80. Located within the secondary degasifier are baflies 82 adjacent the top of the degasifier and other baffles 83 which collect the oil dripping from the baffles 82 and cause it to follow a tortuous path to the bottom of the degasifier. The secondary degasifier is connected at its top by a pipe 04 provided with a valve 85 to the pipe 42 leading to the vacuum pump 43. In this manner the secondary degasifier 80 is maintained under reduced pressure, the vacuum in the degasifier preferably being from 28.5 to substantially 30 inches of mercury as referred to a 30 inch barometer. The secondary degasifier 80 operates in substantially the same manner as the primary degasifier H. In both degasifiers the oil is introduced into the vacuum chamber under pressure and the vacuum chamber is maintained under a high vacuum so as to thereby subject the oil to a sudden shock which causes liberation of any gases and moisture contained in the atomized oil.

The oil is delivered from the bottom oi. the secondary degasifier 80 through a pipe 86 and either through pipe 81 provided with a valve 88 or pipe 89 provided with a valve 90 to one of the storage tanks 9!. The oil is stored under vacuum in these tanks until ready for use. The vacuum is maintained in the storage tanks SI due to the connections of either the pipe 81 or the pipe 89 with the secondary degasifier 80. The oil in the tanks 9| is maintained at approximately the temperature of the atmosphere surrounding the tanks so as to prevent condensation of moisture which might be absorbed by the oil and thereby decrease its insulation value. The temperature of the oil in the storage tanks is regulated by temperature regulators 92 which control the admission of steam through steam pipes 93. The steam exits through pipes 94. An oil pump 95 connected to a motor 96 is provided for withdrawing the oil from each of the tanks 9i and delivering the oil through pipes 91 or 98 to an outlet pipe 99.

A drain pipe I00 provided with valve I02 connects the sump of the secondary filter I5 with the inlet pipe 2 so that the seepage from the secondary filter may be returned for recirculation through the system.

Provision is made for bypassing the oil from the degasifier I6 around the filters 61 and 15 when the process is operated, as in some instances, without mixing adsorbent material with the oil. For this purpose a pipe I03 is connected to the pipe 84, as indicated at 64a. The other end of pipe I03 is connected to pipe I8 leading from the secondary filter I5 to the secondary degasifier 80. The pipe I03 is provided with valve I04. A bypass pipe I05 provided with a valve I05 connects the pipes I3 and I03 so that the oil may be passed through the secondary filter I5 and secondary de- 75 gasifier without passing through the rotary cake filter 61.

The rotary filter 61 has a pipe IIII connected thereto through which compressed air, may be introduced for thoroughly drying and discharging the filter cake after completion of the filtration cycle so as to recover virtually all of the oil which would normally be entrained in the filter cake and return the oil to the mixer. 'lihe air from pipe I01 passes through valve I08'in pipe I09 to the filter 61, valves H0 and III being closed at this time. The oil is discharged from the filter 61 through pipe II2 provided with valve H3, and pipe II4. which returns it to .the

filter 6! is emptyand the cake has. been blown dry by the compressed air, the direction of fiow of the air is reversed so as to blow off the cakes from the filter leaves. This is accomplished by closing valve I00 and opening valves I I0 and I I I. The

cake is then removed by means of a screw conveyor. The filter leaves are thereafter again precoated. In the precoating operation, the oil and precoating material are delivered to the filter 61 by pipe 65. The oil exits from the filter through pipe II provided with valve H6, valve III in pipe 66 being closed at this time. After the precoating operation, the flow through the system is as previously described.

A blotter drier.I20 is also provided for the purpose of drying and impregnating the blotters ,with oil before they are placed in the secondary {filter 15 in those cases where the secondary filter is of the blotter type. The drier is heated by steam which enters through pipe I2I and exits through pipe I226. The drier is connected by pipe I23 to the degasifier I6 so that vacuum may be applied to the drier. The pipe I23 is provided with valves I24 and I25. In operation of the drier, the blotters are subjected to vacuum by opening valve I24 in pipe I23, valve I26 leading to the rotary cake filter 6'I being closed. There after, oil is drawn through the blotters in the drier by opening valve I21 in pipe .I20which connects the outlet of secondary filter 15 with the drier I20. The oil, after passing through the blotters in the drier, flows through pipe I23 and pipe I29 to the rotary filter 61.

The embodiment illustrated in Figure 2 is generally similar to that already described. Referring to Figure 2, the impure oil is admitted through a pipe I40 and after passing through a primary filter I4I, it is pumped by a pump I42 connected to a motor I43 through pipe I44 to the degasifier and mixer indicated generally by the reference numeral I45. The oil from pipe v I44 passes through a heating compartment I46 provided with electric heaters I41 and then passes through a pipe I40 to nozzles I40. The degasifier and mixer is provided with baiiies I50 and I5I and with an agitator I52 and hoppers I53 and I54 and feed devices I55 and I56 generally similar to' those described in connection with Figure 1.

The adsorbent material and the precoating ma.- terial are discharged from the lower ends of the extensions I51 and I58 ofthe hoppers by the feed devices I55 and I56. I

The extensions I51 and I56 of the hoppers I53 and I54 are so located with respect to the nozzles I49 that the adsorbent material and precoating material, as they fall through space in the degasifier, come in contact with the oil sprayed from the nozzles so that the mixture of the adsorbent material and oil takes place while the oil is still in dispersed condition and before it has collected in a body in the mixing chamber I59. In this manner, very intimate contact is obtained between the adsorbent material and the finely dispersed particles of oil. This intimate contact increases the emciency of the adsorbent material beyond that obtained when the adsorbent material is added to a ,body of oil'which is not in finely dispersed particle form.

The degasifier oil having the adsorbent material mixed therewith is then pumped by a pump I60 through pipe I6I to a filter I62 and the oil is withdrawn from the filter through a pipe I63 provided with valve I64. Pipe I63 is connected to a pipe I66 which leads to the degasifier chamber I45, a lock-box I61 and valve I68 being provided in the pipe I66. A vent pipe I65 provided with valve I65a is connected to the upper end of pipe I63. The filtered oil is delivered through pipe I69 provided with valve IBSa. During the pre- 1 opened so as to deliver the filtrate through pipe The degasifier M5 is maintained under reduced pressure by a vacuum pump I'I0 driven by the motor I43 and connected to the degasifier by a pipe III provided with valve H2. The temperature, pressure and degree of vacuum employed in the apparatus illustrated in Figure 2 are preferably the same as those given in connection with the apparatus Illustrated in Figure 1..

In each embodiment the adsorbent material is subjected to vacuum while in a loose, finely divided state simultaneously with its admixture with the oil, thereby greatly decreasing the foaming which occurs when the adsorbent material is added in the usual manner and not under reduced pressure. In each case the mixture of adsorbent material and oil is heated while under vacuum, thereby increasing the ease with which any moisture or gases in the oil or in the adsorbent mate rial may be liberated therefrom by the reduced pressure to which they are subjected. The adoil by agitating the mixture in a tank which is maintained under the desired temperature, thereby insuring thorough contact of the adsorbent material with the oil.

By the term high vacuum is meant from 28.5" to 30" absolute asreferred to'a 30" barometer at sea level. By the term -high pressure is meant from 50 to 250 lbs. gauge per sq. in. By the term an evacuated adsorbent is meant an adsorbent which has been subjected to a relatively high vacuum, for example from 28.5'f to 30" absolute as referred to a 30" barometer at sea level. Such treatment renders the adsorbent material anhydrous so that its adsorbent qualities are greatly increased by virtue of the fact that it is able to adsorb petroleum compounds into the capillaries which were formerly occupied by water.

I have illustrated and described two embodi ments of my invention and have described the preferred conditions under which the process is carried out. It is to be understood, however, that the invention may be otherwise embodied or practiced within the scope of the following claims.

I claim:

1. The method of purifying oihwhich comprises spraying oil in fine particles under pressure into an atmosphere maintained under high vacuum to release moisture and gases therefrom, supplying adsorbent material to the oil while the oil is in dispersed condition, and filtering out the adsorbent materi 11.

2. The method of purifying oil, which comprises spraying oil in fine particles under high pressure into an atmosphere maintained under high vacuum to release moisture and gases therefrom, supplying adsorbent material to the oil while the oil is in dispersed condition, heating the mixture of adsorbent material and oil at a temperature between 250 and 600 F., and filtering out the adsorbent material.

3. The method of purifying oil, which comprises spraying oil in fine particles under pressure into an atmosphere maintained under high vacuum to release moisture and gases therefrom, supplying adsorbent material to the oil while the oil is in dispersed condition and while both the adsorbent material and oil are subjected to high vacuum. and filtering out the adsorbent material.

4. Apparatus for puriiying oil, comprising a heater, 9. degasifier, means for maintaining the degasifier-under high vacuum. a mixer in communication with said degasifier, means for passing the oil through said heater and spraying it in fine particles under high'pressure into said dogasifier, means for supplying adsorbent material to the oil in said mixer, means for heating said mixer, a filter communicating with said mixer, a second degasifier, and means for passing oil from said mixer through said filter to said second deasifier.

5. Apparatus for purifying oil, comprising a heater, a degasifler, means for maintaining the degasifier under high vacuum. a mixer in communication with said degasifier, means for passing. the oil through said heater and spraying it in fine particles under high pressure into said degasifier, means for supplying adsorbent material to the oil in said mixer, means for heating said mixer, a filter communicating with said mixer, a second degasifier, means for maintaining said second degasifier under vacuum, means for passing oil from said mixer through said filter to said second degasiiier, a storage tank in communication with said second degasifler, and means for maintaining said storage tank under vacuum.

8. Apparatus for purifying oil, comprising a heater, a unitary structure providing a degasifler chamber and a mixing chamber in communication with each other, the degasifier chamber being above the mixing chamber, means for passing the oil through said heater and spraying it in fine particles under high pressure into said degasifier, means for maintaining the degasifier chamber under high vacuum, a hopper for adsorbent material, means in the degasifier chamber and in communication with the vacuum therein for feeding adsorbent material from the hopper to the mixing chamber, means for heating said mixer, a filter communicating with said mixer, a second degasifler, and means for passing oil from said mixer through said filter to said second degasifler.

7. Apparatus for purifying oil, comprising a degasifier chamber and a mixing chamber in communication with each other, means for spraying oil in fine particles under high pressure into said degasiiier chamber, means for maintaining said degasifierchamber under high vacuum, means for supplying adsorbent material to the oil while the oil is in dispersed condition, and means in said mixing chamber for mixing the oil and adsorbent material.

RUSSELL P. DUNMIRE. 

